[Info-vax] Floating point emulation of OpenVMS / Alpha / ES

[abrsvc]

On Wednesday, October 12, 2022 at 9:12:10 AM UTC-4, Simon Clubley wrote:
> On 2022-10-11, abrsvc <dansabr... at yahoo.com> wrote: 
> > 
> > I will state that little can be gained from looking at the standard benchmarks unless you know the relationship of them to your own application. I have not found single threaded performance numbers to relate to overall application performance either. That being said, I am aware of many installation using the Charon emulators that perform at or exceed "real" hardware levels. A lot depends upon the application. Some emulators perform JIT, others prescan the code stream and generate the instructions in parallel to their execution. Your mileage may vary. 
> >
> Dan is right. For these types of questions, the only meaningful answer is 
> the one obtained from the OP performing their own benchmarks. 
> 
> Dan, do the emulator vendors support trial licences so the OP can perform 
> these tests before committing to purchase the product ? 
> 
> If so, I would recommend to the OP that this is the path they go down.
> > For full disclosure, I work for the company that created and supports the Charon product stream. I can not comment on the performance of other emulators. 
> >
> Do you ever get user applications that have race conditions on your 
> emulators that were never exposed on their original, slower, hardware ? 
> 
> No reason for asking. Just curious. 
> 
> Simon. 
> 
> -- 
> Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP 
> Walking destinations on a map are further away than they appear.
RE: Race conditions:  As with any "hardware" change, poor code can result in these types of conditions although these days most of these had been addressed many years ago. I do see performance profile changes in how the systems work on a regular basis.  For an Alpha installation for example, real hardware has limits of both main memory and Ethernet throughput speeds.  With modern hardware, the Alpha will think it is connected to a slower network, with newer speeds actually realized.  Also (at least with Charon-AXP)  more main memory is available than with real hardware.  This can help with overall application performance sometimes.

Dan